Our objectives (in this renewal proposal) are to better understand a "gene" in higher organisms, and to help discover how different cells acquire, inherit somatically and later express different gene programs. We utilize the alcohol dehydrogenase gene-system in maize, about which genetic and biochemical information is known. There are two unlinked genes, their modifiers, and 100 mutants. The ADHs are inducible and show different balances of isozymes in different cell types. The approach is eclectic. 1) Mutants involved in regulatory components of the genes will be induced -- especially using accelerated heavy ions, e.g. argon-- chemically selected in pollen (resolution at 10 to the minus 7th power), recovered and analyzed with an arsenal of biochemical and genetic tests. 2) Direct biochemical methods will be applied to ADH synthesis-degradation and to measurements at the message RNA level. 3) Cell and tissue culture methods will continue to provide developmental systems. Qualitative evaluation of radiation biohazard and production of "better" food sources are direct applications of these proposed studies.